The present invention relates to a method of mounting a mouthpiece to the top plate of containers such as drums.
Already publicly known from U.S. Pat. No. 2,267,754 are methods of mounting a tubular mouthpiece having an externally threaded portion on its external peripheral surface to an upright tubular portion formed on the top plate of a drum. This prior art discloses two methods of fixing an annulus or mouthpiece to a collar or tubular portion of a top plate.
The first method comprises the steps of preliminarily forming recesses or notches in the lower end of an annulus and also embossments at the lower end of a collar, fitting the annulus around the collar with the embossments engaged in the recesses, and bending the upper end of the collar outward, whereby the annulus is fixed to the collar.
The second method comprises the steps of fitting around a collar an annulus preliminarily formed with recesses, and pressing outward from inside and deforming the wall portions of the collar corresponding with the recesses, to form embossments which are to be engaged in the recesses, whereby the annulus is fixed to the collar.
However, according to these conventional two methods recesses should preliminarily be formed in the lower end of the annulus in any case. Consequently, it is combersome to design and manufacture the die for producing the annulus, which will entail a high production cost of the annulus.
Especially, since the first method necessitates a positioning operation between the collar and the annulus to successfully interlock the embossments with the recesses, the fixing work requires much labor. Further, now that the second method needs exactly strike-up toward the recesses the portions in the lower end of the collar in compliance with the recesses, the fixing work is still troublesome.
Anyhow, there is a problem that the foregoing conventional methods find a difficulty in automatically effecting the fixing work of the annulus or mouthpiece to the collar or tubular portion.